This invention relates to an improvement in valve actuation apparatus and more particularly to an improvement in the apparatus for actuating rotary filler valves in commercial filling machines.
Standard commercial filling equipment such as used in the beverage industry must perform according to a number of critical requirements dictated by the regulations of the Food and Drug laws for cleanliness of operation and the competitive economics of the particular industry that requires fast reliable equipment so that a high through-put of quality product is obtained.
In the field of beverage filling equipment the Cemco filling machine manufactured by Crown Cork and Seal Co. of Baltimore, Md. is representative of the kind of apparatus which is currently commercially successful. This machine utilizes a central rotating frame to the periphery of which rotary filling valves are attached. They are generally uniformly spaced apart and spatially oriented so as to be in registry with the containers to be filled that are conveyed to and from the filling machine. The filling and venting tubes for conveying beverage or compressed gases to or away from the valves radiate centrally of the circular apparatus, some forming a cone shaped array which is typically fed from the upper part of the filling machine.
The rotary valves themselves are conventionally actuated by arms on a rotary filler valve actuating member encountering wedges located in fixed positions around a stationary ring that surrounds the apparatus. As the central frame rotates and the conveyor with containers moves the containers into registry with the filling nozzel of the valves, the arms on each valve actuating member are adapted to be struck by the stationary wedges to perform the functions of opening the valve to fill the container, close the valve, introduce compressed gases and the like.
Several severe problems are encountered during such normal operation where the actuating wedges impact the protruding arms of the valve actuating member. These problems include filler machine vibration, valve actuating member seal disc wear, wedge wear, and machine down time associated with correcting the problems created by the foregoing, as well as the down time associated with adjustment of the valves, valve springs, and replacement of valve seal discs and bushings. It has been found that the frequency of occurrence of some of the foregoing problems is directly dependent upon the speed of operation which therefore practically imposes a maximum in operating speed for the user, for the operation to be commercially economical.
In particular, the opening and closing wedges for actuating the arms of a Cemco rotary filler valve actuating member have been observed to wear out at a high rate. Due to the shape of the arms, one of which is rotated forward into engagement with the inclined plane of the wedge, the arms, while being positively displaced by this configuration, tend to beat holes or pockets or recesses in the wedges. Wedges worn badly in this manner produce a bad fill upon inspection of the filling process and require replacement.
Unfortunately, the same forces that beat holes in the wedges are transmitted to the valve actuating member seal discs, bushings, valve body, valve body mounts, and vibrate the structural supports and braces of the machine as well as loosening the filler and venting tube connections. Excessive wear in these places and in the wedges means lost production both in time and rejected containers as well as unplanned maintenance.
Similarly, the valve actuating member containing the arms which strike the wedges will tend to misalign the filling ports by overtravelling the desired position. Unfortunately, to overcome this overtravel of the filling ports created by the impact of the wedges on the arms it is often necessary to overtighten the coil spring acting to seal the valve actuating member to the valve body, to prevent unwanted rotation. The additional resistance to rotary movement this creates aggravates the wedge wear and structural problems caused by the resulting increase in impact forces and vibration. The high spring load increases the wear on the valve seal surfaces resulting in additional valve leaks, maintenance and product rejection due to improper fills.
It is therefore an objective of the present invention to provide an apparatus for rotary valve actuation which reduces filler machine maintenance and down time and increases its reliable speed of operation.
It is also an objective of the present invention to reduce or eliminate the present wear rate for a filler machine caused by the use of wedges in all the valve functions.
It is a further object of this invention to reduce vibration in the operation of a beverage container filling machine and the structural problems associated therewith. It is also an objective of this invention to reduce the wear of the rotary filler valve actuating member seals, thereby reducing maintenance costs and product rejection caused by premature leaks developing between the valve actuating member and the seal.
Finally, it is an object of the present invention to provide an apparatus which can actuate a rotary valve in a manner that does not allow filling ports to misalign during the filling, counter pressure, blow down and shut off functions of the valve.